


One Life Left

by celesianmagician



Category: D.Gray-man, Fullmetal Alchemist - All Media Types
Genre: Allen still loves him tho, Canon-Typical Violence, Envy's How to become Human guide, He doesn't recommend it, Homunculus!Allen Walker, Homunculus!Kanda Yuu, M/M, So just blame him for being so pretty, This is all Cross' fault
Language: English
Status: In-Progress
Published: 2018-01-15
Updated: 2018-01-23
Packaged: 2019-03-05 02:34:03
Rating: Not Rated
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 4,019
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13378284
Author URL: https://archiveofourown.org/users/celesianmagician/pseuds/celesianmagician
Summary: It started simply.He hadn't meant for it to happen like this.He'd been bored when he met them. He'd been curious when they got to know each other. He finally got an idea of what those brats had meant when they spouted off about having “precious people.”And then it all went to Hell.“I've looked through some of your memories,” Neah stated, giving that look he'd always been wary of from the mirror. Disappointment was forefront. At least Neah didn't fear him. “You're not that different from the Noah, are you?”“No,” he admitted, smiling sheepishly at the mirror. “I wasn't.”In which Envy fell into the universe of Exorcists, and became Allen.Slowburn.





	1. Envy, meet Cross. Cross, meet Allen

**Author's Note:**

> First posting on AO3!  
> I've combined the events of both the 2003 anime with Brotherhood to make this pan out the way I wanted it to, and completely ignored some of them.  
> In regards to the D.Grayman manga and anime, there are bits of FMA that make it make more sense. This is my attempt to explain my thought process.

He was bored.  
He'd been in this world for a few decades now.  
He'd been extremely active at first.  
Burned down churches and capitol buildings.  
Massacred orphanages.  
Terrorized small towns to the point of superstition.  
Now, he was hiding in the form of a small child, a sickly street urchin he'd shredded out of mercy a few years ago in some town in Germany. Dirty blond hair and beady green eyes. He wasn't all that impressed with this form, but he was tall enough to pickpocket swarmy rich-looking men without attracting too much attention. Not that he'd stick to this form if he was caught, of course. He hummed a little tune as he ducked into a break in the wooden fence, a modest hollowed out shed that had been abandoned quite some time back if the water damage and erosion everywhere was any indicator. He'd turned it into quite the ramshackle home for himself, repairing it and decorating with discarded furniture and shelving. He'd become rather proficient in building what he'd needed.  
Maybe even something like him could make beautiful things one day.  
He counted out the French currency he'd really only just learned and decided that he had enough to splurge on food and maybe something interesting to add to his collection of nicknacks. He'd need a couple more wallets for a warm bed, however. He stood up and walked over to the broken mirror, shifting into an adult form and deciding to play around with his ability. He'd learned he could manipulate his features over three centuries ago when he'd decided on what he had always considered his “cute” form, but hadn't really seen a purpose to doing so very often when it had been so much fun to see his victims falter in the face of a loved one.  
But he was bored, so he did what he wanted.  
First he shifted the short blond hair to long and blood red. He'd seen the hairstyle on a woman in Spain, and the color while he was in Scotland. He gave himself an English woman's large grey eyes and paled his skin a few shades to make himself look more like a nobleman. He shifted his clothes to a warm outfit that had been in style about ten years prior in one of those Scandinavian countries up east and played with the contours of his face until he was satisfied that he was pretty enough. He memorized his new features before reaching over to pick up the big round glasses he had pocketed last month and slid them onto his face. The glasses didn't help him to see any better, but they also weren't hindering him either. He decided he liked them and gave a smile to the form in the mirror. He turned and placed his money into an uninteresting wallet that he tucked into his jacket pocket. He left the space he had claimed as his own in peace, and went down to the shore to a bar he'd heard was decent for the price they charged.  
It was there he met a man that had longer hair than even he had chosen.  
He was beautiful, putting even his new face to shame, even with that odd mask over the right side of his face. So beautiful he was so angry, to the point he was calm again. What an odd feeling.  
He smiled and extended a hand toward the chair next to him.  
“Is this seat taken?” The visable eye raked over his false form before kicking the chair out.  
“What's your name?” the red-head asked, his voice slightly rough as if he'd been drinking a little too much already. He paused before answering.  
“Allen. My name is Allen. What's yours?” Allen responded before seating himself next to the other red-head. Allen was a nice name, noble almost. And most importantly, he liked it. He gave the man a once over, and finally took in the man's outfit. Silver trimming on a black cloak, with silver buttons from collar to the bottom of his torso. Expensive to say the least, and Allen wondered if it was a uniform, with how impersonal it seemed.  
“Cross Marion,” Cross smirked and waved over for another round of what he already had. “What's a pretty boy like you doing in a place like this?”  
Allen snorted at the pick-up line. He'd heard far too many similar ones when he'd gone to bars as a woman hoping for free alcohol.  
“Could ask you the same question, darling,” he shot back easily, making Cross grin widely. “But then I'd have to believe that it wasn't for the sole purpose of meeting me.” He flipped a lock of hair behind him pompously. The waitress winked at both of them as she set two servings of alcohol in front of them. Allen picked up his glass and took a sip.  
The wine Cross had picked he knew was worth far more than he'd collected. Worth more than the collection of trinkets on his shelves.  
“Where do you work that you can afford this?” He found himself asking without thinking about it first. Cross blinked at him and tilted his head, seemingly reassessing Allen.  
“The Church,” Cross stated slowly, “sometimes pays its exorcists very well.” Allen had to wrack his brain for what he knew about the Catholic Church. For some reason all he could think about was that fake Sun God religion he'd helped Lust and Gluttony create with that old fat guy...  
...That Gluttony ended up eating after the pipsqueak and his brother blew through town.  
Oh, he remembered the Church now.  
“Exorcist? What, you're the fucker the normal priests call in when someone's possessed or something?”  
“Or something.” Cross smirked, looking away and downing the rest of his glass. The waitress came back with a tray filled with food that she dished out between the two red-heads, topping off their wine. Allen felt himself drool at the buffet he'd been given. Even without an actual stomach, Allen could appreciate well made food. The waitress left again and Allen pushed some of his hair behind his ear.  
“Do demons exist, do you think?” He was curious. He'd attended a sermon or twenty, thought the Church was full of morons but that the stories were interesting.  
Now he was wondering if there was any truth to them.  
Heh. Truth.  
Cross took another sip.  
“Not the kind you're thinking of,” he admitted, lowering his voice. “We call them “Akuma,” which is Japanese for “demon,” but they really aren't.” Allen blinked and leaned towards his companion, starting to eat a little. “Akuma are created by a man called the Millenium Earl. He shows up when someone is deeply grieving a recently deceased loved one and offers to bring them back to life. He drags the soul back down here and puts it in a skeleton, a doll.” Human transmutation? But for the soul instead of the body. Interesting. And probably just as dangerous.  
“Everyone has lost someone,” Allen stated honestly. “So what happens then, what's the cost?” Cross smiled at him.  
“He then orders the Akuma to kill the person who brought it back.” Allen flinched sympathetically.  
He remembered what happened when his “father” turned him into a Humunculus. He was sure becoming an Akuma was just as bad. He shook his head at the blurred memory of his childhood friends' corpses surrounding him and tuned back in to the present.  
“After that, the Akuma have only one purpose: to evolve through killing.”  
“So, they become weapons.” Just like him and his “siblings.” Because they aren't people anymore, regardless of if they have had desires, or emotions, or friends.  
“There're armies of them everywhere,” Cross confirmed.  
“Well... Shit.” Allen stated eloquently. “How do we fight them?”  
“You don't. That's what exorcists are for.”  
“Considering you're the first one I've seen?” In decades, at least. And Allen had been to quite a few places. More than once. “There can't be many of you.” Cross snorted into his drink, sitting back from his half-finished meal.  
“There aren't. Unfortunately, the only effective weapons against Akuma and the Earl are picky. They won't allow just anyone to fight, so recruitment is a pain in the ass.”  
“Even with your charming personality and penchant for shitty pick-up lines?” Allen cooed, finishing his plate and picking up his glass again.  
“I'll have you know that my pick-up lines are top of the line,” the masked man shot back. “I've never not gotten what I wanted.” Allen snickered into his wine. Cross rolled his eye and pulled out a small box. He opened it and pulled out a tiny cube that was encased in what looked like a pair of gears. And tossed it to Allen, who only caught it on reflex. He held the cube in his bare hands for a moment, and in that moment the souls that made up his Stone was quiet. Contemplative, almost. He looked up at Cross.  
“Is something supposed to happen?” The man grinned.  
“Only if you were compatible, which you obviously aren't.” Allen rolled his eyes as he handed the cube back to him, which was then placed back inside its box and put away.  
“What is it?”  
“God's Crystal. Its common name is Innocence. Once it finds a compatible human, it either transforms into a weapon that human can use or combines with that human physically and becomes parasitic.” Human. Well, Allen figured that just meant it would never react to him. One less problem he'd have to face, at least.  
The conversation moved to less serious topics and the waitress continued to top off their glasses with the wine. Allen ended up nice and drunk, hanging off of his new equally drunk friend. He woke up the next morning as the little spoon on Cross' bed with one of the masked-man's hands resting on his stomach under his shirt. He reached down and felt for his pants, relieved he still had them on. He pushed the offending hand out from its resting place and rolled over, rolling off of the bed and landing in a heap on the floor.  
It took some effort to find the man's bathroom in the tiny hotel room (running water? How did Cross score _running water_? Did the humans install it everywhere while his back was turned? When did they even discover it?) and more besides to locate his coat that had been draped over a chair. A quick check into his wallet and Allen blinked.  
He hadn't spent a single Franc. And he couldn't very well remember Cross even pulling anything resembling a wallet out.  
He tucked his wallet back into his coat and slid back into bed with Cross, who didn't seem to even notice. He closed his eyes and dozed off.  
Cross woke up about two hours later and froze.  
Allen started at the sudden shift as Cross leapt from the bed.  
“What?”  
“Did—did we?” Cross blushed bright red. Allen flat out laughed at the panic the red-head went into.  
“No, we didn't,” he soothed when he finished laughing. “But you're warm, so get back here. I'm still tired.”  
Cross laughed and instead went to the bathroom.  
“Bastard,” Allen mumbled, pulling the blankets up around him. He heard the water running for Cross' shower and sighed before rising fully himself, stretching to work out stiff muscles. When Cross came out, clean and dressed drying his hair, Allen took his turn, swiping some of Cross' clothing for himself. Cross chuckled.  
“Anything for you, Princess,” he cooed. Allen stuck his tongue out and disappeared into the bathroom. He pawed through the hygiene products and scoffed. A tiny ass room, but near top-of-the-line soaps? _Rich people_.  
Cross was looking at a cute little golden ball when Allen came out.  
“So, I've got a mission to Italy,” Cross stated. “Want to join me?”  
Allen didn't need to think too hard on that. Really, Cross was just too pretty. And so interesting. It wasn't even fair.  
“Of course I do.” Cross' smile was blinding. The bastard. “I just need to grab my things.”  
And so Allen packed up the knicknacks he'd accumulated over the past few decades and burned his hideaway to the ground, effectively erasing the proof that he'd ever been there.  
Let's see that fucker Hohenheim find him now. Allen was sure he'd seen the man around, and had actually been looking for a reason to leave his little home since.  
Having a companion was a nice feeling. And Allen figured that when he was bored with Cross, he could always just kill him. It certainly wouldn't be the first time he'd done it.  
He met up with Cross at the train station, the wind blowing his red hair around him, suitcase held tight, and hopped aboard with his new friend.


	2. The Campbell House

**Summary for the Chapter:**

> Cross drags Allen across the continent. Allen is not happy. But, then he gets promised food.

Allen lay on the bed, book in hand from a impressive pile he'd borrowed from the Madame off to the side that he'd already worked through, staring at the ceiling.  
Why?  
Cross. Fucking. Marian.  
Bastard drags him halfway across the continent and then _leaves him by himself_.  
And not even a fancy hotel this time. Oh no.  
“ _I have a friend we can stay with_ ,” he'd said. Yeah. Friend.  
Allen hadn't been able to sleep at all the past few nights they'd been in Cardinale.  
How could he, when all he could hear every night was Cross making more “friends”? Not to mention the girls' actual clients. Even the rather lovely pastry shop down the way wasn't enough to temper Allen's failing mood.  
The urge to kill Cross and be done with it was great. He had it all planned out, too. And he wouldn't even disappear afterward, soaking up all the “I'm sorry for your loss”s and other condolences. Maybe he'd even get gifts and money for doing the world a great service.  
Then Cross would turn around and flash him _that smile_ and Allen knew he couldn't do it.  
Really, the man was just too pretty.  
But Cross wasn't here right then, so going through his plan to rid the world of a beautiful womanizer was on the menu.  
He daydreamed for another hour, refining his plans and wondering just how messy he should make it, before lifting the book back up and continuing it.  
He had just finished it when the exorcist walked into the room. Allen gave him a flat look as Cross grinned.  
“All done, Princess. No Innocence here, but there were plenty of targets.” From what Cross said about how Akuma work, that meant the Earl at least _thought_ there was something there. He wondered if Cross was keeping whatever it was to himself.  
Then reminded himself that it didn't really matter. He was with Cross to alleviate boredom, not save the world.  
“Please tell me we're leaving today. It's still early enough to catch a train,” Allen pleaded. The exorcist snorted.  
“Yeah. We need to start back up north for a few things.” He paused then and tilted his head. “You know... I haven't seen you with any of the girls. We can stay another night. It would improve your--”  
The book very nearly broke Cross' nose.  
Pity.

A few more towns (and scandals. Who knew priests were so much fun?) later, they ended up in England. Allen mused that he hadn't been there in quite a while.  
They disembarked and Allen stretched with his arms above his head.  
“We have an inn we're staying at tonight, right?” he was a whiner, and he freely admitted it. Cross smiled, picking up Allen's suitcase from where he'd set it down.  
“Better. I've got a couple friends here we can stay with.” Allen made a face.  
“The last time you said that, we ended up staying in a _brothel_ for a week.”  
“I promise its not a brothel. It even has hot water.” Cross then glanced at Allen judgingly. “And anyways, what kind of man doesn't like being surrounded by beautiful women?”  
“The kind that has more important things to worry about. Like _not hearing his friend get it on with random whores all night_.”  
“To each his own,” Cross quoted simply and moved forward to lead the way. Allen fell into step behind him, following him down the street to a hidden path leading to a large house.  
“Who lives here?!” Allen shouted, stopping in the path when he saw the whole thing.  
“A couple friends of mine,” Cross reiterated. “You'll like them, I promise. Oh, they're going to _love_ you.” Allen frowned. This really wasn't what he had signed up for, he couldn't help but think. Just how far down the rabbit hole had he fallen when he'd put on this face?  
And more importantly, how many of Cross' friends would he meet? Would they like him?  
Allen shook his head and readjusted his glasses for the eighth time before hoisting his suitcase back up from where Cross had set it down and running after his companion.  
He was really starting to regret the glasses.  
He made it to the door while Cross gave five hard knocks.  
Allen set his suitcase down next to Cross' and nervously played with the hem of his sleeves. It never ended well when he included rich people in his schemes, as they tended to not play their parts correctly. Allen took the time to glance at Cross for any sort of cue, only to see the bastard completely calm. Jerk. He turned back to the door as it started to open and paused at the young adult that opened it.  
Long dark hair, big smile, eyes like the sun that had for so long been denied to him...  
Allen was staring, and he knew it.  
“Uhm... hi?” The man (teenager?) laughed.  
“Cross, you didn't tell me your friend was _pretty_ ,” he chided easily. He extended his hand to Allen. “My name is Mana Campbell.”  
“Allen,” he introduced, shaking the offered hand.  
“Allen what?”  
...Shit. He knew he forgot something.  
“Just... just Allen.” Golden eyes slid to meet the single red one, never losing his smile. Cross gave a non-committal shrug.  
“Well, 'Just Allen,' come on in. My brother has been dying to meet you!” He dragged Allen inside, leaving Cross to carry in the luggage. Allen managed to keep on his feet as Mana carted him around to what Allen assumed to be a den, or some kind of conference room made homey. He could just hear the ending of a piano piece as they approached the door, and when Mana pushed it open Allen caught sight of the male sitting at a beautiful white and gold piano.  
Virtually identical to Mana, only with a more subtle smile and short hair. He stopped playing as the door swung open and had turned to look at the new arrivals.  
“Neah, Cross brought his friend! Allen, this is my brother Neah.”  
“Oh, good,” Neah chirped before Allen could respond, hopping up and crossing the room. He grabbed Allen's face and turned it side to side, inspecting it and squishing it a little. Then smiled. “I approve.” He let go and swept past them, calling for Cross.  
“Eh?” Allen blinked, reaching up to try to figure out what Neah had done to his face.  
Mana started laughing.  
“What? What's happened? Why'd he do that?!” He was spazzing a bit, but in his (limited) experience with humans, _they just didn't do that for no reason_! Mana just walked back out, leaving Allen in the doorway. “Mana?! Answer me!” And he ran after the twins.  
Allen never did get his answer.  
“So, the Innocence in Italy?” Mana asked, handing Allen and Cross tea.  
“Headquarters isn't sure about it, but the surge of Akuma suggests that there was something there.” Allen tilted his head.  
“Where, exactly, are we headed now?” Cross never did mention, did he? Not that it really mattered, Allen just liked knowing where he was.  
“That's a secret~” Cross grinned. Allen picked up a nearby book and threw it at his head. “Ow! What was that for?!”  
“Being a little shit,” he explained easily. He took another sip of his tea as the twins giggled at his responses.  
“Hey, Cross, can we keep him?” Neah asked as Cross rubbed his head.  
“Only if it's you taking him,” the redhead sniped, giving Allen a glare.  
“I'm not a pet, you know.”  
“You'd be a horrible pet,” Cross griped. “You're like that cat that tried to claw my face off in France.”  
“Then you're like that dog that wouldn't go outside and peed on the wall instead.”  
“How have you two survived each other?” Mana asked in awe. Allen gave a shrug. Sometimes he wasn't entirely certain.  
“He's funny?” And beautiful, and charming, and had a knack for getting stuff for free, and always knew where he was and how to stay under the radar when they managed to get into trouble. Which turned out to be quite often.  
The list was actually very long, if Allen were honest with himself.  
He was starting to like pretending he was.  
Neah rolled his eyes. "You must be some kind of saint to deal with him like you have. How long have you two been together again?"  
Cross started counting on his fingers and Allen tilted his head back to think.  
“A...month?” Cross tried.  
“Five weeks?” Allen estimated, trying to remember all the places they went to and the amount of time they spent at each. The two red-heads looked at each other and then shrugged at the twins.  
Mana shook his head a little.  
“Okay, so we still need to hunt down the Heart, right?” Neah volunteered. “So any other leads?"  
The three humans through around ideas and locations while Allen sat back and listened, occasionally tossing out a random fact about a location he knew. He put the pieces together for what they were even looking for easily.  
Although... Just what had he gotten himself into here?  
Traveling with an exorcist that is looking for Innocence and fighting hordes of Akuma was fine. That was in Cross' job description.  
Traveling with an exorcist that is looking for Innocence, fighting Akuma, AND staging a resistance against the Millennium Earl with two teenagers in order to _save the goddamned world?_  
Allen didn't remember signing up for this.  
He ended up wandering around the room, debunking strange things around the continent, and looking at the books and other items on display.  
“What about that cave in that temple in the Ottoman Empire that anything that goes near it dies?” Neah stated ineloquently, his eighth try at finding a sign of Innocence.  
“Carbon monoxide and other noxious gases. One whiff will kill just about anything, and the way the ancients built the temple helps keep it localized,” Allen answered before turning around. “And now you're just using me for amusement, aren't you.”  
“What? No,” Neah immediately defended. “It's just that with you able to answer these, we don't have to waste time going to find out ourselves!” Allen just stared at him.  
Cross, being the complete jerk that he is, laughed.  
“It is really nice that you know all this,” Mana interjected before another book found its way to Cross' face. “Where did you learn it?”  
Allen shrugged, “I like reading.” The excuse was a believable one, and Allen figured that admitting he'd gone to all these places wouldn't end in his favor.  
He turned back around to inspect the décor, missing the shared looks from the three humans behind him.  
“Oi, Princess,” Cross called out. “Come sit down. You're pacing like a caged animal.”  
“Am not,” Allen defended before walking over to the couch Cross was seated on. Mana shot a look at the clock.  
“We should go ahead and go to the dining hall. No doubt the cooks have already finished dinner,” he announced, standing.  
Allen perked up instantly.  
“There's food?”  
“Of course there is,” Cross laughed. “It's gonna be your favorites, too.”  
All right. He'll save the world.  
As long as he gets fed.


End file.
